Hebmann hoffmann



(ModeL) H. HOPFMANN.

Alarm Look.

Patented Sept.21,1880.

N. PETERS, PHOTO-UTHOGRIPNER. WASHINGTON. D. C.

UNITED, STATES PATENT OFFICE.

HERMANN HOFFMANN, OF NEW YORK, Y.

ALARM-LOCK.

SPECIFICATION forming part of Letters Patent No. 232,497, dated September 21, 1880. Application filed May 28,1580. (ModeL) To all whom it may concern:

Be it known that I, HERMANN HOFFMANN, of New York, in the State of New York, have invented a new and useful Improvement in Locks, of which the following is a specification.

In the accompanying drawings, Figure I represents a front view of my improved lock. Fig. II is a cross-section at line A of Fig. I; and Fig. III shows a longitudinal section at line as w of Fig. I, and also the key.

13 is the back plate of the lock, through which the same is attached to the door. Upon this plate the bolt 0 is arranged, which, it'the lock is to be used on a door, is provided with a knob or projection, D, to operate the same by hand. B is thestaple-plate, into which the bolt is moved and attached to the door-frame in the usual manner.

Above the bolt 0 a tumbler-lever, E, is arranged, pivoted at one end and acted upon by a suitable spring, F. This tumbler-lever E has the usual projection, b, which, in eitherposition, locked or unlocked, falls into one of the notches (I, provided on the top of the bolt. A projecting arm, E, is attached to this tumblerlever to operate the same by hand. On the under side of this lever E the tumbler-plate E is attached, fitting into a recess made in the bolt 0 and extending to the lower surface of the bolt 0, and which is acted upon by the key so as to lift the projection b from the notch in the bolt to allow the key to act upon the bolt to move it either way.

J J are the usual notches on the bottom of thebolt, into which the ward of the key fits to operate the bolt.

G is the key-hole, made circular and of a size for the stem or body 01 of the key to pass through. This key-holeis covered by a spring, H, which is made at the keyhole of such a width as to cover nearly the whole length of the ward of the key in any position.

L is a suitable bolt, to which a bell, K, is attached, operated by a suitable hammer, m, attached to the spring H, to give an alarm when the spring is moved and after the same recoils. The key is represented in Fig. III.

The ward n is hinged to the stem or body 61 and turns freely on its joint-pin. This ward is turned to lie in a corresponding slot in the stem d, as shown at 3 in dotted lines, Fig. III, when the key is carried in the pocket.

When the key is to be used for operating the bolt the ward n is placed in the position as shown at 1,forming a continuation of the stem d, in which position the same can be passed through the circular key-hole G, where the ward comes in contact with the spring H, to which sufficient motion must be given to allow the wholelength of the ward 'n to be forced inside of the back-plate B. When the Whole length of the ward has been passed through the key-hole a slight turning of the key will cause the action of the spring H against the extreme end of the Ward to turn the same until the ward comes at right angle to the body or stem d, as shown at 2, Fig. III, and is retained in' that position between the plate B and spring H, as shown in Fig. III, ready to operate upon the bolt 0. The recoil of the spring H causes the hammer to to strike the bell K, and thus to give the desired alarm.

N is a pin sliding on the staple-plate B, capable of being moved into a suitable recess,

bolt at the inside whenever desired.

I do not claim a hinged bit in the end of a key; but

What Iclaim as m y invention, and desire to secure by Letters Patent, isv

1. In a lock provided with a suitable bolt and tumbler, the spring H, covering the circular key-hole G at the inside of the lock, and

S, in the bolt 0, for the purpose of locking the provided with a hammer, m, in combination with a bell, K, substantially as set forth.

2. In a bolt-lock, a circular key-hole, Gr, covered on the inside with a spring, H, provided with a hammer, m, in combination with a key having the ward at hinged at the end of jthe stem cl, arranged to operate substantially in the manner and for the purpose herein described.

HERMAN N HOFFMANN. 

